Traditional systems used to pump heat to and from a room to reduce or increase air temperature have several shortcomings. In particular, they become inefficient at smaller capacities, they generate an uncomfortable level of noise in occupied spaces from the mechanical components, they can be cumbersome and even dangerous to install, they often require dedicated electrical power outlets to manage surge loads, and they often use toxic and environmentally harmful refrigerants to provide heat pumping.
A common alternative to these traditional systems is to simply use a basic fan (e.g., a ceiling fan or a standing fan). A typical fan can provide an apparent and virtually silent improvement in comfort level derived from either the enhancement of the body's natural cooling system or increase in the delivery rate of warmed air to a user of the fan. This effect is provided simply by the localized increase in the mass flow of air, not by any reduction or increase in air temperature. In humid climates this effect is greatly reduced and the apparent relief is largely eliminated because the air cannot easily absorb any additional water vapor. In hot, humid environments, when trying to provide a cooling effect, a fan, at best, simply stirs the hot, moist air around, ensuring uniform discomfort. At worst, the mechanical and electrical work done by a fan will actually warm the air being moved, thereby reversing the desired effectiveness of the appliance in providing cooling relief to the user. In cold, dry environments, additional air flow from a fan without a true increase in air temperature can actually cause the user to feel colder and less comfortable by the same mechanism that provides the cooling effect in warmer conditions.
As such, there remains a need for cooling or heating an occupied space.